The transducer / potentiometric sensor is an electromechanical device containing a resistance element connected by a movable slide contact. The sliding contact movement produces a linear, logarithmic, exponential change of resistance, and so on, depending on the way in which the resistance wire is rolled. Potentiometers available on the market consist of several types, namely carbon potentiometers, wire wound potentiometers and metal potentiometers.
The carbon potentiometer is a potentiometer made of carbon material the price is quite cheap but the potentiometer potency is very low usually the price of resistance will be very easily changed due to contact shift. The wire wound potentiometer is a potentiometer that uses a very small nickel wire coil of its cross-sectional size. The research of this type of potentiometer depends on the size of the wire used and the tidiness of the rolling. The metal potentiometer of the film is a potentiometer using a metal material overlaid with an insulating material
The carbon and film metal potentiometers are rarely used for industrial control because they wear out quickly. The wire wound potentiometer is a potentiometer that uses a fine wire wrapped around a metal rod. The accuracy of a potentiometer depends on the size of the wire. The wire used is usually a nickel wire. The use of a potentiometer for position control is practical because it requires only one excitation voltage and usually does not require a complicated signal processor. Weakness of potentiometer usage is mainly:
· Fast wear out due to friction
· Frequent noise occurs, especially when the change of position and saaat happened loose contact
· Sensitive to impurities
Linear potentiometer is a potentiometer that changes the resistance very fine with the number of turns up to ten times the turn (multi turn). For the purposes of positioning a linear potentiometer sensor utilizing a change in resistance, protection is required if its measurement range exceeds the rating, the high linearity of the result is easy to read but be careful with friction and backlash generated, the resolution is limited to 0.2-0.5%. In Rotary Potentiometer, When the wipers rotate then the total resistance will also change. The shaft of the wiper is usually affixed to the rotating axle.